We love this building kit. T received it Christmas 2012. Today he spends as much time with it as he did when first unwrapped it. When it comes to toys that says volumes!
When playing with it he is quietly content. His focus is intense. He can spend hours fitting the pieces together, disassembling and reassembling. So a definite boon is this toy helps him work on concentration skills.
In this era of STEM education I love how it teaches engineering. His dad says it is great how realistic the elements of construction reflects real life. Even the screwdriver works like a DeWalt. The only con is it is made of plastic. A metal set would be si much better. We're thinking about adding to the set (maybe a Caterpillar bulldozer) for his 5th birthday.
In case you're wondering the set is by EZ Build.